Bradford stunned Arsenal on penalties as they continued to defy the odds to reach the Capital One Cup semi-finals - as well as increase the mounting pressure on Gunners manager Arsene Wenger.

Quoted as 2000/1 outsiders at the start of the season, the League Two outfit were still as big as 100/1 with Sky Bet before Tuesday night's clash to lift the trophy but they are now just 25/1 with BetVictor.

The spot-kick specialists won their ninth successive penalty shoot-out 3-2 after Thomas Vermaelen, who earlier scored a header three minutes from normal time to equalise Garry Thompson's first-half volley, struck a post with the final kick.

Defeat for Arsenal reduces their chances of ending their long trophyless run and now William Hill make it 4/6 that Wenger never lifts another as Gunners manager.

The Frenchman is also 7/2 to have left the club by the end of the season while Sky Bet have cut him from 25/1 to 5/1 to be the next Premier League manager to leave his post.

Sky Bet's Chris Spicer said: "Failing to beat Bradford would be worrying enough if Wenger had named an experimental squad, but the fact that such a strong side named rings real alarm bells.

"Arsenal's board are certainly not one to make rash decisions but serious questions are surely being asked with the current side looking so uninspiring.

"Full credit to Bradford though, who have come in from 2000/1 - fortunately they were not backed at that price but some punters did get on at as long as 500/1."

Meanwhile Aston Villa are 4/1 with bet365 after storming to a 4-1 victory at Norwich in Tuesday night's other quarter-final tie.

Substitute Andreas Weimann hit a second-half brace to turn the clash around after Brett Holman had cancelled out Steve Morison's opener.

Christian Benteke cracked in a fourth during stoppage time to move Villa a step closer to Wembley.

Arsenal's demise has enforced Chelsea's position at the head of the market and they are now 5/6 with Sky Bet although they don't play their quarter-final with Leeds until Wednesday December 19.

Swansea are 5/1 ahead of their quarter-final clash with Championship side Middlesbrough (18/1) on Wednesday night.

In the night's only Premier League clash, Sunderland beat Reading 3-0 to climb out of the relegation zone.

The result saw Royals boss Brian McDermott cut further to 2/1 favourite to be the next Premier League manager to leave his post with Sky Bet while Sunderland counterpart Martin O'Neill has drifted to 7/2.

Reading are now just 1/4 to be relegated with Blue Square and 888sport, whereas Sunderland are out to 4/1 with Ladbrokes and Coral.